TITANIUM-STEEL REDUCER Russian patent published in 2003 - IPC

FIELD: joining by welding of pipes from different materials unweldable by traditional methods of welding by melting. SUBSTANCE: reducer is made in form of bushing from titanium alloy and bushing from stainless steel lap-welded with each other by diffusion welding. Stainless bushing is located on the outside of titanium alloy bushing. Lap welding is effected over cylindrical surfaces with mechanical engagement with each other in form of alternating circular projections and hollows of threaded profile. Diffusion interlayer is not in excess of 20 mcm thick. Bushings cylindrical surfaces in zone of lap welding joint have, at least, one cylindrical step. Thickening of lap welding joint may be made on external or internal side of reducer. EFFECT: higher serviceability of reducer in vital high-temperature pipelines operating under conditions of vibrations and variations of medium temperature in pipeline. 4 cl, 3 dwg